Neeson, Harris duel in Run All Night

Liam Neeson and Ed Harris are looking out the window of a suite on the 12th floor of Manhattan's Ritz-Carlton hotel.

The view is a winter wonderland.

Before the veteran actors is a snow-covered Central Park, but on this recent day the sky is a vibrant blue, the sun is out and the brutal winter the city has suffered through the past three months has begun to thaw.

"I do eight miles in that park every day when I'm in New York," Neeson tells Harris.

"I don't run, but power walk."

"All weather?" Harris asks.

"Yeah," Neeson says.

"Raining, snow. I've got all the gear."

Neeson is 62, Harris is 64 and their schedules would leave most 20-year-olds exhausted.

Neeson has become Hollywood's most bankable action star with his Taken trilogy a $US1 billion ($A1.31 billion) franchise and a regular stream of other hits in the genre released over the past three years.

The latest is Run All Night, an action thriller set in New York pitting Neeson as alcoholic hitman Jimmy Conlon and Harris former mob boss Shawn Maguire.

Conlon and Maguire are lifelong friends.

But, when Conlon's son, played by Swedish actor Joel Kinnaman, becomes entangled with Maguire's drug addict, wannabe gangster son, (Boyd Holbrook), a code between families is broken and war declared.

Not only was it the first time Neeson and Harris worked together, but it was the first time they met.

"It's amazing, you know," Harris, needling Neeson about his blockbuster action star status at the age of 62.

"I just wish they were paying him better."

Harris, proving plenty of stamina, shot Run All Night at the same time he was performing eight times a week in the Broadway play, The Jacksonian.

"He'd get a police escort to the theatre every night," Neeson, firing back at Harris, laughs.

Harris corrects his friend, saying the police were only called in a couple of times to get him to the theatre on time.

There's plenty of action in Run All Night, but the highlights are the quiet scenes between Neeson and Harris.

When it's suggested watching the actors going head-to-head is like watching Bjorn Borg and John McEnroe in one of their epic Grand Slam finals, the actors deflect the praise.

"It wasn't a mano a mano type thing," Neeson said.

"Egos were left outside the door and it was 'Here I am, I'm a canvas, we have this lovely scene to do, let's breathe it and do it'."